Utility of Adding Magnetic Resonance Imaging to Computed Tomography Alone in the Evaluation of Cervical Spine Injury: A Propensity-Matched Analysis.

STUDY DESIGN: Adult patients who received computed tomography (CT) alone or CT-magnetic resonance imaging (MRI) for the evaluation of cervical spine injury. OBJECTIVE: To evaluate the utility of CT-MRI in the diagnosis of cervical spine injury using propensity-matched techniques. SUMMARY OF BACKGROUND DATA: The optimal evaluation (CT alone vs. CT and MRI) for patients with suspected cervical spine injury in the setting of blunt trauma remains controversial. METHODS: The primary outcome was the identification of a cervical spine injury, with decision for surgery and change in management considered secondarily. A propensity score was developed based on the likelihood of receiving evaluation with CT-MRI, and this score was used to balance the cohorts and develop two groups of patients around whom there was a degree of clinical equipoise in terms of the imaging protocol. Logistic regression was used to evaluate for significant differences in injury detection in patients evaluated with CT alone as compared to those receiving CT-MRI. RESULTS: Between 2007 and 2014, 8060 patients were evaluated using CT and 693 with CT-MRI. Following propensity-score matching, each cohort contained 668 patients. There were no significant differences between the two groups in baseline characteristics. The odds of identifying a cervical spine injury were significantly higher in the CT-MRI group, even after adjusting for prior injury recognition on CT (odds ratios 2.6; 95% confidence interval 1.7-4.0; P < 0.001). However, only 53/668 patients (8%) in the CT-MRI group had injuries identified on MRI not previously recognized by CT. Only a minority of these patients (n = 5/668, 1%) necessitated surgical intervention. CONCLUSION: In this propensity-matched cohort, the addition of MRI to CT alone identified missed injuries at a rate of 8%. Only a minority of these were serious enough to warrant surgery. This speaks against the standard addition of MRI to CT-alone protocols in cervical spine evaluation after trauma. LEVEL OF EVIDENCE: 3.

Risk Factors for Prolonged Opioid Use Following Spine Surgery, and the Association with Surgical Intensity, Among Opioid-Naive Patients.

BACKGROUND: There is a growing concern that the use of prescription opioids following surgical interventions, including spine surgery, may predispose patients to chronic opioid use and abuse. We sought to estimate the proportion of patients using opioids up to 1 year after discharge following common spinal surgical procedures and to identify factors associated with sustained opioid use. METHODS: This study utilized 2006 to 2014 data from TRICARE insurance claims obtained from the Military Health System Data Repository. Adults who underwent 1 of 4 common spinal surgical procedures (discectomy, decompression, lumbar posterolateral arthrodesis, or lumbar interbody arthrodesis) were identified. Patients with a history of opioid use in the 6 months preceding surgery were excluded. Posterolateral arthrodesis and interbody arthrodesis were considered procedures of high intensity, and discectomy and decompression, low intensity. Covariates included demographic factors, preoperative diagnoses, comorbidities, postoperative complications, and mental health disorders. Risk-adjusted Cox proportional hazard models were used to evaluate the time to opioid discontinuation. RESULTS: This study included 9,991 patients. Eighty-four percent filled at least 1 opioid prescription on discharge. At 30 days following discharge, 8% continued opioid use; at 3 months, 1% continued use; and at 6 months, 0.1%. In the adjusted analysis, the low-intensity surgical procedures were associated with a higher likelihood of discontinuing opioid use (discectomy: hazard ratio [HR] = 1.43, 95% confidence interval [CI] = 1.36 to 1.50; and decompression: HR = 1.34, 95% CI = 1.25 to 1.43). Depression (HR = 0.84, 95% CI = 0.77 to 0.90) was significantly associated with a decreased likelihood of discontinuing opioid use (p < 0.001). CONCLUSIONS: By 6 months following discharge, nearly all patients had discontinued opioid use after spine surgery. As only 0.1% of the patients continued opioid use at 6 months following surgery, these results indicate that spine surgery among opioid-naive patients is not a major driver of long-term prescription opioid use. Socioeconomic status and pre-existing mental health disorders may be factors associated with sustained opioid use following spine surgery. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Characterization of the encoding properties of intraspinal mechanosensory neurons in the lamprey.

Proprioceptive sensory inputs are an integral part of the closed-loop system of locomotion. In the lamprey, a model organism for vertebrate locomotion, such sensory inputs come from intraspinal mechanosensory cells called "edge cells". These edge cells synapse directly onto interneurons in the spinal central pattern generator (CPG) circuit and allow the CPG to adjust the motor output according to how the body is bending. However, the encoding properties of the edge cells have never been fully characterized. To identify these properties and better understand edge cells' role in locomotion, we isolated spinal cords of silver lampreys (Ichthyomyzon unicuspis) and recorded extracellularly from the lateral tracts where edge cell axons are located. We identified cells that responded to mechanical stimuli and used standard spike sorting algorithms to identify separate units, then examined how the cells respond to bending rate and bending angle. Although some cells respond to the bending angle, as was previously known, the strongest and most common responses were to bending velocity. These encoding properties will help us better understand how lampreys and other basal vertebrates adapt their locomotor rhythms to different water flow patterns, perturbations, or other unexpected changes in their environments.

The impact of hepatitis C virus infection on 90-day outcomes following major orthopaedic surgery: a propensity-matched analysis.

INTRODUCTION: The impact of hepatitis C virus (HCV) infection on outcomes following major orthopaedic interventions, such as joint arthroplasty or spine surgery, has not been effectively studied in the past. Most prior studies are impaired by small samples, limited surveillance for adverse events, or the potential for selection bias to confound results. In this context, we sought to evaluate the impact of HCV infection on 90-day outcomes following joint arthroplasty or spine surgery using propensity-matched techniques. MATERIALS AND METHODS: This study utilized 2006-2014 claims from TRICARE insurance. Adults who received spine surgical procedures, total knee and hip arthroplasty were identified. Covariates included demographic factors, a diagnosis of HCV and medical co-morbidities defined by International Classification of Disease-9th revision (ICD-9) code. Outcomes consisted of 30- and 90-day mortality, complications and readmission. A propensity score was used to balance the cohorts with logistic regression techniques employed to determine the influence of HCV infection on post-operative outcomes. RESULTS: The propensity-matched cohort consisted of 2262 patients (1131 with and without HCV). Following logistic regression, patients with HCV were found to have increased odds of 30-day complications (OR 1.87; 95% CI 1.33, 2.64; p < 0.001), 90-day complications (OR 1.55; 95% CI 1.16, 2.08; p = 0.003) and 30-day readmission (OR 1.46; 95% CI 1.04, 2.05; p = 0.03). CONCLUSION: HCV infection was found to increase the risk of complication and readmission following spine surgery and total joint arthroplasty. Patients should be counseled on their increased risk prior to surgery. Health systems that treat a higher percentage of patients with HCV need to consider the increased risk of complications and readmission when negotiating with insurance carriers.

Cardiac-specific YAP activation improves cardiac function and survival in an experimental murine MI model.

RATIONALE: Yes-associated protein (YAP), the terminal effector of the Hippo signaling pathway, is crucial for regulating embryonic cardiomyocyte proliferation. OBJECTIVE: We hypothesized that YAP activation after myocardial infarction (MI) would preserve cardiac function and improve survival. METHODS AND RESULTS: We used a cardiac-specific, inducible expression system to activate YAP in adult mouse heart. Activation of YAP in adult heart promoted cardiomyocyte proliferation and did not deleteriously affect heart function. Furthermore, YAP activation after MI preserved heart function and reduced infarct size. Using adeno-associated virus subtype 9 (AAV9) as a delivery vector, we expressed human YAP (hYAP) in the adult murine myocardium immediately after MI. We found that AAV9:hYAP significantly improved cardiac function and mouse survival. AAV9:hYAP did not exert its salutary effects by reducing cardiomyocyte apoptosis. Rather, AAV9:hYAP stimulated adult cardiomyocyte proliferation. Gene expression profiling indicated that AAV9:hYAP stimulated expression of cell cycle genes and promoted a less mature cardiac gene expression signature. CONCLUSIONS: Cardiac-specific YAP activation after MI mitigated myocardial injury, improved cardiac function, and enhanced survival. These findings suggest that therapeutic activation of YAP or its downstream targets, potentially through AAV-mediated gene therapy, may be a strategy to improve outcome after MI.